There is a requirement for wireless communication devices to have increased spectral efficiency and reduced power consumption. Advanced modulation schemes can provide increased spectral efficiency, but these can require transmitters that can amplify a signal having a non-constant envelope.
A polar modulator enables a transmitter for a non-constant envelope signal to be implemented in a power-efficient manner. In a polar modulator, a phase component and an amplitude component of a modulation signal are processed separately. A carrier signal is phase modulated by the phase component. The phase modulated carrier signal has constant amplitude, and therefore can be amplified in a power-efficient amplifier. The amplitude modulation is applied to the phase modulated carrier signal after the amplification.
Therefore, there is a requirement for an improved polar modulator.